Exactly what G98/G99 registration is, whether your system was registered, and how to fix it if not — including what it costs and who can do it.
Book a documentation reviewInstaller gone bust hubHad a problem with my GivEnergy battery which had decided to charge and discharge to a very limited extent. From AI, felt that the problem was probably a calibration issue on the Battery Management System, but which I could not fix myself. So contacted Solar Tech Support, and Ron was brilliant in being able to identify, confirm and fix the issue remotely and very speedily. Thoroughly recommend this outfit
Excellent knowledge and service. Ron responded to my initial query really quickly (same day), and confirmed that he could add extra panels and battery to my existing GivEnergy setup - something I’d been told by other installers wouldn’t be possible. Two weeks later (!), scaffolding was up and Ron and his team were on site to fit the extra 5 panels and two more GivEnergy batteries. I now have a truly optimised system, which has made the most of the south facing roof space I have, without having to start again with new kit. I’m now generating enough on the solar to fill my batteries, and avoid using the grid. I’ve also exported far more than before. Brilliant experience, well recommended.
Excellent knowledgeable company which sorted out my Givenergy issues that no one else could sort! Initial remote diagnosis into what unit(s) where faulty which enabled me to confidently source and buy a replacement at a good price and on so doing Solar Tech then got my system up and running remotely within an hour or two. A1 service!
The Solar Tech Support company was the only one to respond to a request for someone to supply and fit a new inverter for our solar panels after our old one finally expired after 26 years. Ron kept us well informed throughout, came and ascertained that the issue was down to the inverter having failed then sourced and fitted a new one. He got the system up and running again, set up the wi-fi performance feedback and took away the old inverter for disposal. By acting promptly and fitting the job around existing commitments we were able to get our solar power unit back in operation with minimal delay in the short while before we were due to go away for a week. The work was carried out very professionally and we were asked to confirm that all was in order the following day. I was impressed that, having recently taken on additional work for GivEnergy customers we were able to keep our solar panel down-time to a minimum. I would highly recommend for prompt attention and first-rate service.
Brilliant. He fitted a new dongle and set the system up properly. Even better, he explained why the storage batteries don't work in a power cut - not correctly wired up - expensive to fix, but a simple turn of the master switch will give emergency power. He is the third technician to look at this issue and the only one to resolve it. Friendly and appoachable, comes when he says he will and reasonable charges. What's not to like!
Following the storm my givenergy system was effectively useless. I contacted STS after seeing other reviews and recommendations and they delivered. My system was a challenging one, but is now back working as it was - this was all done remotely by them using their own software and expertise. Great service, thank you!
Every solar or battery system connected to the grid must be registered with the local Distribution Network Operator — the company that owns and manages your electricity network. This is a legal requirement under UK grid regulations.
The installer notifies the DNO that a system has been installed. This is a simple paperwork exercise — the DNO does not need to approve it, only be informed. Most solar-only home systems fall under G98. The installer files it within 28 days of commissioning.
Larger systems, even with export limited, require formal approval before installation begins. The DNO reviews the system design against grid capacity and may request modifications. Once approved, installation can proceed. G99 is more rigorous than G98 and takes longer to process retrospectively.
Most energy suppliers require either DNO registration or an MCS certificate before accepting SEG applications. Without one you cannot register and will not be paid for exports — typically £200–£795 per year lost.
Many insurers require systems to be MCS-certified or DNO-registered before they will cover solar-related damage. If something goes wrong and the system is unregistered, a claim may be denied.
Qualified electricians will ask for evidence of registration before agreeing to work on or modify an unregistered system. Liability concerns mean many will simply decline.
Conveyancers and surveyors check for DNO registration when you sell. Its absence can delay the sale, reduce the sale price, or require expensive remediation before exchange.
The installer's responsibility: G98 or G99 registration was your installer's legal obligation, not yours. If they failed to file it — or went bust before doing so — you inherit the compliance gap. The good news is that retrospective registration is almost always possible and is not expensive.
Missing registration does not stop your system from working — it continues to generate and your battery continues to charge. The problems arise when you need something from a third party.
Octopus, E.ON, EDF, and most other SEG suppliers require either an MCS certificate or proof of DNO registration before they will open a SEG account. Without one, you cannot be paid for energy exported to the grid.
Typical lost income: £200–£795 per year depending on system size and export rate.
Home insurers often require evidence of compliant installation (MCS certificate, DNO registration) before covering solar-related losses. A roof fire or storm damage claim could be rejected if the system was not properly registered at the time of installation.
Potential exposure: £10,000–£50,000+ in uninsured losses.
A qualified electrician taking on work on an unregistered installation takes on liability risk. Many will simply decline until the system is brought into compliance. This can make servicing, fault repairs, or system upgrades difficult to arrange.
When you sell, your solicitor will raise the missing registration in conveyancing. The buyer's solicitor, surveyor, and mortgage lender may all require evidence of compliance before proceeding. This can delay the sale by weeks and often requires price reductions or expensive indemnity insurance.
Typical impact: 2–8 weeks delay or £5,000–£30,000 price reduction.
All of this is fixable: Filing retrospective G98 notification typically costs £50–£200 and takes 1–2 weeks. Once registered, every one of the problems above is resolved. Don't delay — the longer you wait, the more export income is lost and the greater the insurance exposure.
Follow these steps in order. Many homeowners discover their registration already exists — it's worth checking before arranging a new filing.
Your DNO is the company responsible for the electricity cables and infrastructure in your area — not your energy supplier. There are several regional DNOs covering the UK.
Major UK DNOs: UK Power Networks · Electricity North West · Northern Powergrid · ScottishPower Energy Networks · SSE · National Grid Electricity Distribution
Contact your DNO and ask them to search their records for G98 notification or G99 approval at your address. Installers sometimes filed registration without providing the homeowner a copy.
Provide them with: your full property address, approximate installation date, and the installer's name if you know it.
If a record exists, request a copy in writing — keep it alongside your other system documentation. If no record exists, proceed to step 3.
Response time: 1–2 weeks. Always get their response in writing.
The Microgeneration Certification Scheme maintains a public database of all certified solar installations. An MCS certificate is accepted by most SEG suppliers and insurers in place of formal DNO paperwork.
If found: download and save it — this may be enough for your SEG supplier or insurer without needing formal DNO registration. If not found: proceed to step 4 (system may pre-date MCS or installer was uncertified).
If your system is up to 16 A per phase in total (3.68kW single-phase, 11.04kW three-phase), it requires G98 notification. A retrospective filing is straightforward and can be done by any MCS or NAPIT-registered electrician.
Larger systems require formal G99 approval. Retrospective approval is more involved and varies by DNO, but is achievable in most cases.
Contact your DNO directly, explain the situation (installer ceased trading, no G99 approval on record), and provide system details and any available documentation. The DNO will advise on their retrospective process — this may include a site inspection or engineering review.
G99 retrospective approval can take several weeks and cost £200–£1,000+ depending on DNO requirements. Contact your DNO early and keep records of all correspondence.
Most of these resources are free or very low cost. Start with the DNO check and MCS search before spending anything.
Can search their records for existing registration, provide copies of any documentation already filed, and advise on the retrospective registration process for your specific system size.
Find yours at energynetworks.org or on your electricity bill. Most respond within 1–2 weeks. Free.
Free public database of all MCS-certified solar installations. Search by your postcode to find and download your MCS certificate. This may be enough for your SEG supplier or insurer without formal DNO registration.
Free. Systems from 2012 onwards are usually listed. Pre-2012 installs may not appear.
Can file retrospective G98 notification on your behalf, advise on whether G99 applies, and perform any site inspection needed as part of the filing. Search "MCS solar electrician" or check the NAPIT register online.
Cost: £50–£200 for G98 notification. G99 processes vary.
Search find.company-information.service.gov.uk to confirm whether the installing company has dissolved and to find administrator contact details. Administrators may hold installation records that could help with your filing.
Free. Sole traders are not registered at Companies House — use MCS or DNO routes instead.
We can review your existing documentation, identify what is missing, advise on the most efficient route to compliance, and coordinate with DNO or electricians on your behalf.
Book a documentation reviewAction checklist: (1) Identify your DNO at energynetworks.org — (2) Ask DNO to search for existing registration — (3) Check mcscertified.com for your MCS certificate — (4) If neither exists, contact an MCS-registered electrician for G98 filing — (5) Keep all confirmations in writing.
We can review your existing documentation, confirm what registration exists, and advise on the fastest route to compliance — whether that's downloading your MCS certificate or coordinating a retrospective G98 filing.
Due to unprecedented demand we’re currently only carrying out on-site work in Yorkshire, and replies are taking up to 7 days. Remote diagnostics continue for the whole UK as normal.
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